野村茂治教授退職記念論文集In Honor of Prof. Shigeharu NOMURAThe recent upsurge of the employment rate of Japanese women seems to cause a widening of earnings disparities among married-couple households. Based on panel data derived from the Japanese Panel Survey of Consumers (the Institute for Research on Household Economics), we explore women’s employment and decisions on their career path at their first birth (continue to work / leave / change jobs), and examine the impacts on the family earnings inequality among them. Our findings confirm the following three points. First, wives in their 20s and 30s are likely to work if their husbands’ earnings are low (Douglas-Arisawa’s Law). Second, wives’ earnings contribute to increase family earnings inequality until 2003 but to equalize it after 2008. Third, among couples of working mothers, although wives’ earnings have an effect to equalize family earning inequality regardless of wives’ career decisions, the effect is larger among the couples of wives who choose to continue to work after the first birth, compared to the couples in which wives chose to leave or change jobs after the first birth.